Faulty Reasoning

Faulty Reasoning The opinion article by Garland Allen, “A Dangerous Form of Eugenics is Creeping Back Into Science,” (The Scientist, February 6, 1989) shows that a dangerous form of antiscientific thought is creeping back into science. Allen would have us believe that there are aspects of the biological organization of human beings that should remain forever unknown. The opinion and the justifications for it are based on faulty reasoning, unsubstantiated accusations, and downright

By Bruce Bridgeman | May 1, 1989

Faulty Reasoning

The opinion article by Garland Allen, “A Dangerous Form of Eugenics is Creeping Back Into Science,” (The Scientist, February 6, 1989) shows that a dangerous form of antiscientific thought is creeping back into science. Allen would have us believe that there are aspects of the biological organization of human beings that should remain forever unknown. The opinion and the justifications for it are based on faulty reasoning, unsubstantiated accusations, and downright inaccuracy.

Allen uses all of the tricks of the polemicist’s trade, including the juxtaposition of disapproved ideas with past, unrelated outrages. Why is present research on genetic links to alcoholism, for instance, related to eugenics? Perhaps the writer fears future attempts to remove those with “alcoholic” genes from the population; the research might also lead to a cure for the disorder, however. The discovery of the genetic basis and subsequent treatment of phenylketonuria (PKU), or even of schizophrenia, are cases in point. We can’t stop doing research because someone might misuse it in the future, any more than we can stop making automobiles because a drunken driver might misuse one.

Many of Allen’s statements are simply false, or based on ignorance of biology; it is not true that “it is virtually impossible to disentangle the learned from the biologically determined aspects of human behavior.” There is no such thing as a biologically determined aspect of human behavior, and no such thing as a learned behavior without a genetic contribution. This is just the sort of simplistic gloss of gene-environment conflict that led to eugenic arguments in the first place. All behaviors are governed by subtle combinations of genetic and environmental influence, in ways thai we must, understand better if we are to have a scientific psychology. Further, it is not impossible to statistically separate genetic and environmental influences on populations. There is a large literature on this methodology.

After informing us that heredity and environment cannot be separated, Allen concludes that genetic tendencies toward one or another trait are minuscule by comparison to our overall ability to adopt new behaviors. It is refreshing to see a scientist come to such a firm conclusion in this area, especially an author who has just stated that such conclusions are virtually impossible. Apparently the problems of definition evaporate when the conclusions weigh on the side of the environment, for Allen has no difficulty in finding a “perfectly good social explanation for why crime and rates of alcohol abuse increase” during times of crisis. (Can he name a time that isn’t a time of crisis?) Are these the same behavioral patterns for which genetic in- fluences cannot be found, because the patterns cannot be defined? Internal inconsistency is not the mark of a convincing case.

BRUCE BRIDGEMANProfessor of Psychology and Psychobiology University of California Santa Cruz, Calif